The present invention relates to machines which are particularly useful for sawing diamonds and other precious stones.
The conventional diamond sawing machine includes a stationary frame rotatably mounting on its front end a diamond sawing disc and pivotably mounting on its rear end a swingable arm adapted to carry the diamond between a pair of holders or dops and to bring the diamond into engagement with the sawing disc. The sawing disc is supported in a vertical position by a holder having a pair of horizontal trunnions received in open sockets formed in a pair of horizontally spaced posts on opposite sides of the swingable arm carrying the diamond holder, the sockets being lubricated with oil.
Many diamond sawing machines of the foregoing type are now in use. One of the drawbacks in the known machines is that the lubricating oil within the sockets in which the diamond holder trunnions are rotated, tends to be ejected from the sockets by centrifugal forces, thereby requiring the sockets to be frequently relubricated. Another drawback in the known machines arises when the sawing of a relatively large and expensive diamond is not completed at the end of a day's work, in which case the diamond and its holder are removed from the machine, placed in a safe overnight, and then reapplied to the machine the next day for completing the sawing operation; in the known machines, considerable time and skill are required to reapply the diamond and holder to the machine such that the diamond is located precisely at the same angular position with respect to the sawing disc as when the diamond and holder were removed from the machine at the end of the preceding day's work.